P320W Support Notes
All contents copyright (c) 2005 ZyXEL Communications Corporation.
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traffic will be blocked by P320W. To help users get rid of the problem and configuration tasks, P320W
will create firewall policy automatically to allow incoming traffic if NAT is enabled in the P320Ws.
Firewall FAQ
What is a network firewall?
A firewall is a system or group of systems that enforces an access-control policy between two networks.
It may also be defined as a mechanism used to protect a trusted network from an untrusted network. The
firewall can be thought of two mechanisms. One to block the traffic, and the other to permit traffic.
What makes P320W secure?
The P320W is pre-configured to automatically detect and thwart Denial of Service (DoS) attacks such as
Ping of Death, SYN Flood, LAND attack, IP Spoofing, etc. It also uses stateful packet inspection to
determine if an inbound connection is allowed through the firewall to the private LAN. The P320W
supports Network Address Translation (NAT), which translates the private local addresses to one public
address. This adds a level of security since the clients on the private LAN are invisible to the Internet.
What are the basic types of firewalls?
Conceptually, there are three types of firewalls:
1.
Packet Filtering Firewall
2.
Application-level Firewall
3.
Stateful Inspection Firewall
Packet Filtering Firewalls generally make their decisions based on the header information in individual
packets. These header information include the source, destination addresses and ports of the packets.
Application-level Firewalls generally are hosts running proxy servers, which permit no traffic directly
between networks, and which perform logging and auditing of traffic passing through them. A proxy
server is an application gateway or circuit-level gateway that runs on top of general operating system such